A new performance abstraction method for the Maximum Likelihood decoder (mlD) in the Multiple-Inputs Multiple-Outputs (MIMO) channel is presented. The method is based on a model of the iterative equalize and de-map de...
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ISBN:
(纸本)9781479980918
A new performance abstraction method for the Maximum Likelihood decoder (mlD) in the Multiple-Inputs Multiple-Outputs (MIMO) channel is presented. The method is based on a model of the iterative equalize and de-map decoder for MIMO channel and abstracts the performance of the MIMO link into a set of effective Signal-to-Noise power Ratio (SNR) values corresponding to the different streams. The proposed Iterative MIMO Effective SNR (IMES) approach is general and allows for the use of different modulation constellations and independent channel encoding on the MIMO streams. The low complexity IMES technique can be applied to different MIMO configurations and can be combined with existing approaches such as Exponential Effective SNR Mapping (EESM) and Mean Mutual Information per Bit (MMIB) - for link performance abstraction of MIMO OFDM systems. Performance results show that the proposed method delivers accurate performance abstraction across configurations with different numbers of transmit antennas and input constellation modulation orders.
A new performance abstraction method for the Maximum Likelihood decoder (mlD) in the Multiple-Inputs Multiple-Outputs (MIMO) channel is presented. The method is based on a model of the iterative equalize and de-map de...
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ISBN:
(纸本)9781479980925
A new performance abstraction method for the Maximum Likelihood decoder (mlD) in the Multiple-Inputs Multiple-Outputs (MIMO) channel is presented. The method is based on a model of the iterative equalize and de-map decoder for MIMO channel and abstracts the performance of the MIMO link into a set of effective Signal-to-Noise power Ratio (SNR) values corresponding to the different streams. The proposed Iterative MIMO Effective SNR (IMES) approach is general and allows for the use of different modulation constellations and independent channel encoding on the MIMO streams. The low complexity IMES technique can be applied to different MIMO configurations and can be combined with existing approaches -such as Exponential Effective SNR Mapping (EESM) and Mean Mutual Information per Bit (MMIB) - for link performance abstraction of MIMO OFDM systems. Performance results show that the proposed method delivers accurate performance abstraction across configurations with different numbers of transmit antennas and input constellation modulation orders.
This paper analyzes the performance of various decoders in a two-user interference channel, and some improved decoders based on enhanced utilization of channel state information at the receiver side are presented. Fur...
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This paper analyzes the performance of various decoders in a two-user interference channel, and some improved decoders based on enhanced utilization of channel state information at the receiver side are presented. Further, new decoders, namely hierarchical constellation based decoders, are proposed. Simulations show that the improved decoders and the proposed decoders have much better performance than existing decoders. Moreover, the proposed decoders have lower decoding complexity than the traditional maximum likelihood decoder.
With the rapid increase in the growth of digital broadcast technologies, there has been a demand for high data rate, power, and bandwidth efficient transmission, which, today, is aided by the high-performing low-densi...
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With the rapid increase in the growth of digital broadcast technologies, there has been a demand for high data rate, power, and bandwidth efficient transmission, which, today, is aided by the high-performing low-density parity check (LDPC) codes. In this paper, we explore a novel alternative scheme to the LDPC decoder that performs detection, demodulation, and decoding jointly, coined the joint detector demodulator decoder (JDDD). We test the JDDD through simulation using the modulation schemes defined in the DVB-S2 satellite broadcasting standard. The JDDD is a more recently developed algorithm to the sum-product algorithm (SPA) that is used in decoding the LDPC codes. The JDDD is optimal over a modulated additive white Gaussian noise/intersymbol interference (ISI) channel when resources are sufficient, with the main constraint limiting the algorithm being the availability of computing resources. In this paper, we compare the performance of the system using the JDDD against that of the LDPC decoder. The main result is that the JDDD is able to outperform the iterative detector decoder (IDD) at shorter codeword lengths, when resource requirement is smaller, while the increase in computational requirements tends to favor the IDD at longer CWLs.
In this paper, a new medical image-adaptive watermarking technique is proposed in which embedding of the watermark is done in low frequency coefficients for achieving high robustness using an adjustable dynamic streng...
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In this paper, a new medical image-adaptive watermarking technique is proposed in which embedding of the watermark is done in low frequency coefficients for achieving high robustness using an adjustable dynamic strength factor. The low frequency coefficients are modeled using Gaussian distribution to design a Maximum Likelihood (ml) decoder. The decoder recovers the watermark with the help of side information containing the adjustable dynamic strength factor, position of blocks (used for embedding), mean and variances of low frequency coefficients. The method contributes towards a highly flexible and easily adjustable dynamic strength factor for achieving the best imperceptibility with the highest robustness. The validity of the new technique is verified against various attacks and the results are compared with other watermarking schemes. The proposed technique is found to generate better results.
The rapid growth of commercial cellular and personal communication systems has increased the demand for high data rate, power and bandwidth efficient transmissions. Advanced coding and modulation techniques are suitab...
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ISBN:
(纸本)9781509059324
The rapid growth of commercial cellular and personal communication systems has increased the demand for high data rate, power and bandwidth efficient transmissions. Advanced coding and modulation techniques are suitable candidates for this purpose as the potential to reduce the symbol period is often limited by the multipath-induced intersymbol interference (ISI). In this paper, a scheme that jointly performs detection, demodulation, and decoding is proposed and is coined the joint detector demodulator decoder (JDDD). The JDDD is a generalization of the previously proposed joint Viterbi detector decoder (JVDD) that performs detection and decoding of binary phase shift keying (BPSK) modulated signals over ISI channels. The JVDD algorithm performs two operations on a trellis: the first operation computes metrics and retains a set of survivors, while the second operation performs parity checking on the survivors to return the minimum metric legal codeword (MmlC). The JDDD algorithm also has a similar structure but the number of states in JDDD trellis is a factor of the number of symbols defined by the modulator and the characteristics of the ISI channel. In this paper, the performance of the proposed JDDD algorithm is evaluated over an ISI channel.
Recently, a framework was given for linear error-correcting network codes (LENCs) over cyclic networks on commutative rings. When the alphabet is considered as a rational power series ring, an LENC is referred to as a...
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Recently, a framework was given for linear error-correcting network codes (LENCs) over cyclic networks on commutative rings. When the alphabet is considered as a rational power series ring, an LENC is referred to as a convolutional error-correcting network code (CENC). Recently, a metric was introduced for these codes based on the minimum rank distance. In this paper, a new metric is introduced for ring-based LENCs over cyclic networks based on the Hamming distance, which is referred to as the network Hamming distance. Then, some connections between maximum distance separable (MDS) LENCs and classical MDS codes are obtained. Finally, the network Hamming free distance is given for CENCs, which plays the role of the free distance for convolutional codes.
Tail-biting convolutional codes (TBCC) have been applied in many recent modern communication standards such as LTE and WIMAX. TBCC is a method applied in conventional convolutional code by replacing a fixed zero-tail ...
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ISBN:
(纸本)9781467364997
Tail-biting convolutional codes (TBCC) have been applied in many recent modern communication standards such as LTE and WIMAX. TBCC is a method applied in conventional convolutional code by replacing a fixed zero-tail with tail-biting data constrains to achieve a better coding efficiency. This modification makes the decoding process becomes much more complex. Due to impracticality of the optimum decoding algorithm such as brute force, recently some suboptimum algorithms have been developed but it still leaves a large amount of computation due to the iterative nature wherein the number of iterations depends on the received codeword causes inefficient system for implementation, especially for real time applications. In this paper we offer a new algorithm that is specific to low cost hardware implementation. Low cost criteria are addressed to minimum amount of computation for each decoding process. In addition to causing smaller area consumption, the lack of computing process will also make decoding processing time becomes faster. This algorithm that we call reverse trellis algorithm also offers a fixed amount of computation regardless to the received codeword, thus will not require extra memory consumption as it being on an implementation. Taking a case study on TBCC configuration for LTE, proposed algorithm requires 5712 adding operations and 3008 inverting operations. A significant decrease compared to 286736, adding 143360 inverting for Brute Force and 45079976738816 adding 1099511627776 inverting for all possible fixed tail ml decoder. In the performance of BER, reverse trellis algorithm is able to deliver improved by more than 1 dB compared to direct terminating ml decoder.
In this paper, we propose a new hardware-efficient ml decoding algorithm for a spatial modulation scheme which is basically constructed by serially concatenating maximum-ratio receive combiners with traditional slicer...
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ISBN:
(纸本)9781479945917
In this paper, we propose a new hardware-efficient ml decoding algorithm for a spatial modulation scheme which is basically constructed by serially concatenating maximum-ratio receive combiners with traditional slicers. With respect to complex multiplications, the new algorithm has a greatly reduced decoding complexity compared to the conventional one, especially, for higher-order modulation. This is mainly because the complexity of the slicer is practically negligible without regard to a modulation order.
This paper proposes a high-rate spatial modulation transmission scheme based on the concept of Spatial Constellation (SC) and SC codewords introduced in [1]. In the proposed scheme, transmitted signal vectors are gene...
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ISBN:
(纸本)9781479944811
This paper proposes a high-rate spatial modulation transmission scheme based on the concept of Spatial Constellation (SC) and SC codewords introduced in [1]. In the proposed scheme, transmitted signal vectors are generated by multiplying spatial SC codewords with constellation symbols drawn from a conventional QAM or PSK constellation. The entries of SC codewords will determine how the constellation symbols are weighted and which transmit antennas among a total of n_T transmit antennas are activated to transmit the signals. Different SC codewords allow us to have different ways to transmit the constellation symbols. Thus, information bits are born not only by constellation symbols but also by SC codewords. The additional spectral efficiency offered by SC codewords is proportional to the number of SC codewords which can be designed for each antenna configuration. A new low-complexity maximum-likelihood (ml) decoder is also devised for signal recovery. In addition, a theoretical union bound on the bit error probability is derived. Simulation results, supported by the theoretical upper bound, are given to compare bit error rate (BER) performance of the proposed scheme with those of existing MIMO transmission counterparts in the literature for various antenna configurations.
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